Packs of young people cause chaos in Hollywood

LOS ANGELES (AP) - Los Angeles authorities say packs of young people rampaged through Hollywood, knocked down people and stole cellphones before a police sweep halted the marauding.

Lt. Ray Valois says 12 people were arrested - 11 of them under 18.

Valois says calls began coming in around 8:30 p.m. Tuesday that youths were robbing people and stealing T-shirts and other items from businesses, mainly on Hollywood Boulevard. He says groups of youths would split off and re-form.

More than 100 police officers were called in. Valois says it appears the attackers were loosely organized through social media, including some Web messages urging people to gather in Hollywood "to riot."

However, he says it's unclear whether the attacks were prompted by the George Zimmerman verdict in Florida.